Anomalous insertion of the superior oblique tendon onto the superior rectus muscle causing congenital superior oblique palsy.

Congenital superior oblique (SO) palsy is often associated with anomalies of its tendon, increased tendon laxity being the most common. Rarely, the tendon lies in an abnormal location nasal to the superior rectus (SR) muscle, either attaching to the sclera or to Tenon's capsule. We describe a case of a child who presented with abnormal head posture and exotropia. The orthoptic evaluation revealed a left hypertropia and V-pattern exotropia. The motility pattern and the Parks three-step test were suggestive of left-sided SO palsy. Intraoperatively, the left SO tendon was very lax and was absent from its usual insertion. Further exploration revealed it to be inserted entirely to the nasal border of the SR muscle, with no scleral attachment. This tendon was advanced to its normal attachment to the sclera, and 11 mm inferior oblique recession was also performed. Postoperative alignment was satisfactory.